<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>调试</title>
</head>
<body>
<script>

  var name = "张三";
  debugger;
  // 结合开发工具进行调试
  console.log("李四");
  alert(name)

</script>
</body>
</html>